The E-Myth Revisited by Michael Gerber

A true small business bible that reframes the way you need to approach your startup in order to give it legs. One huge piece of the is the massive gap between working 'in' your business versus 'on' your business. A lesson that when unlearned proves consistently fatal. There are plenty of other incredibly helpful framing tools here like a full breakdown of the difference between the technician, the manager, and the entrepreneur.

Fairly strategy light which is fine, not every book should or could provide absolutely everything.